This invention relates generally to optical equipment and more particularly concerns apparata for applying a block on a lens blank in preparation for mounting on a grinder.
The placement of a block on a lens must be accurate if the lens is to be correctly positioned in the frame to match the prescription of the patient.
To accomplish this placement, existing blocker type devices presently provide for entering data, displaying a target, displaying the spectacle rim shape and applying the block. However, computations within blockers are minimal. Targets are of a fixed shape with allowance for particular job requirements and judgement is required of the operator to center marks on the lens blank relative to the target. In some cases, clamping devices are used to hold the lens blank. Manually operated blockers are subject to a varying force when the block is applied to the lens blank.
It is therefore an object of this invention to provide a lens blocker which minimizes the need for operator judgment in blocking a lens. It is a further object of this invention to provide a lens blocker which routinely leads an operator through a target customizing process to tailor the target placement and/or configuration to the individual lens, patient and frame characteristics of each job. Another object of this invention is to provide a lens blocker which applies a constant, limited force to the lens during the blocking process. And it is an object of this invention to provide a lens blocker which operates in a variety of modes for direct operator input for calculating the placement of the block based on operator input, or so as to receive frame and/or patient data from measuring equipment and/or from a database. A further object of this invention is to provide a lens blocker that automatically compensates for parallax. Yet another object of this invention is to provide a lens blocker which will allow the operator to confirm the accurate location of the segment relative to the optical center in a multi-focal lens.